Weight-adjustable dumbbell

ABSTRACT

An improved weight-adjustable dumbbell includes a carrier base, a plurality of weights, and two selection devices. The weights are mounted one by one respectively outside said carrier base, each having a through hole. The two selection devices are mounted respectively at two lateral sides of the carrier base, having an adjusting rod and an adjusting unit. The adjusting rod has a first guidance and a second guidance. The adjusting unit has a rotatable member and a retaining piece. The rotatable member has at least one retaining portion for stopping the rotatable member from axial movement, and a guide lug slidably engaging the guide groove. The retaining piece slidably engages the second guidance for stopping the adjusting rod from axial rotation. When the rotatable member is rotated, the adjusting rod can be driven to axially reciprocate through the through holes of the weights to select the desired number of the weights.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to exercise apparatuses, and more particularly to a weight-adjustable dumbbell.

2. Description of the Related Art

A conventional dumbbell for holding by the user's one hand is made of one-piece metal by casting and its weight is invariable. When the user intends to change the dumbbell's weight, the user has to buy another dumbbell of different weight, thereby being uneconomic. Then, a weight-adjustable dumbbell is developed, having a handgrip for holding by the user and a plurality of disk-shaped weights mounted to two ends of the handgrip. Although the weight-adjustable dumbbell is variable in its weight by changing the number of the weights, it is inconvenient for the user that the weights have to be serially connected one by one at the two ends of the handgrip.

There was a weight-adjustable dumbbell, as shown in FIG. 1, developed in the early 1990s to improve aforementioned problem. The weight-adjustable dumbbell is comprised of a main body 1, two support frames 4 located at two ends of the main body 1, numerous pairs of tunnels 5 formed respectively on the two support frames 4, numerous pairs of rectangular weights 2 mounted one by one outside the main body 1, a plurality of connecting bars 6 each interconnecting one pair of the weights, and a latch 3 detachably inserted into one pair of tunnels 5 and engaging against a bottom side of the corresponding connecting bar 6. The user can insert the latch 3 into different pair of tunnels 5 to change the total weight of the dumbbell. However, when the latch 3 is inserted into the tunnels 5, if the user operates the dumbbell for exercise improperly or for a long time, the latch 3 may be subject to deformation or rupture and then the weights may depart from the dumbbell, thereby endangering the user.

In the late 1990s, a weight-adjustable dumbbell, which weights can be changed by a screw rod, is developed. The user can turn a driving member to drive the screw rod to transversally reciprocate, thereby adjusting the weight of the dumbbell. However, the pitch between each two threads of the screw rod is commonly very small and the threads are arranged very closely, so that the user has to spend much time on turning the screw rod to adjust the weights as required, thereby causing inconvenience for the user. To improve the problem, a transmission mechanism can be installed in the dumbbell to reduce the time spent on turning the screw rod. However, the dumbbell installed with the transmission mechanism becomes structurally complex and its production cost is greatly increased.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide an improved weight-adjustable dumbbell, which is structurally simplified and which weights are conveniently and accurately adjustable.

The foregoing objective of the present invention is attained by the improved weight-adjustable dumbbell, which is comprised of a carrier base, a plurality of weights, and two selection devices. The carrier base includes two support frames and a handgrip mounted between the two support frames for holding by the user. The weights are mounted respectively outside the two support frames one by one, each having a through hole. The two selection devices are mounted respectively at two lateral sides of the carrier base, having an adjusting rod and an adjusting unit. The adjusting rod has a first guidance and a second guidance. The adjusting unit has a rotatable member and a retaining piece. The rotatable member has at least one retaining portion engaging against the support frame of the carrier base for stopping the rotatable member from axial movement, and a guide lug slidably engaging the guide groove of the adjusting rod. The retaining piece slidably engages the second guidance of the adjusting rod for stopping the adjusting rod from axial rotation. When the rotatable member is rotated, the guide lug moves along the first guidance to drive the adjusting rod to axially reciprocate through the through holes of the weights to select the desired number of the weights.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a conventional dumbbell;

FIG. 2 is a partial exploded view of a first preferred embodiment of the present invention;

FIG. 3 is a schematic view of the first preferred embodiment of the present invention.

FIG. 4 is a sectional view of the first preferred embodiment of the present invention.

FIG. 5 is a schematic view of the first preferred embodiment of the present invention at work.

FIG. 6 is a sectional view of the first preferred embodiment of the present invention at work.

FIG. 7 is a schematic view of a second preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 2-4, a weight-adjustable dumbbell 10 constructed according to a first preferred embodiment of the present invention is comprised of a carrier base 11, a plurality of weights 31, and two selection devices 41.

The carrier base 11 includes two support frames 12 and 14 corresponding to each other and each having two half-shell members 121 and 122 (141 and 142), two through holes 16 and 17 running respectively through each two half-shell members 121 and 122 (141 and 142) and being different in diameter, four rod members 15 fixedly connected respectively between the corners of the two support frames 12 and 14, two hook-like lugs 18 protruded outside a top end of each support frame 12(14), a hollow handgrip 22 slidably fitted onto the adjusting rod 42 and mounted to the through holes 17 and located between the two support frame 12 and 14 for holding by the user. The handgrip 22 has two slots formed respectively on a periphery of two ends thereof and corresponding in alignment with the guide channel 422 of the adjusting rod 42.

The weights 31 are mounted respectively outside the support frames 12 and 14 of the carrier base 11 and made of metal, each having a through hole 32 running therethrough, and two hook-like coupling portions 34 formed respectively on two sides of each weight 31. The coupling portions 34 are different from one another in height, such that the weights 31 can be mounted upon one another by the coupling portions 34 and then mounted outside the two support frames 12 and 14.

The two selection devices 41 are mounted respectively at bilateral sides of the carrier base 11, having an adjusting rod 42 and an adjusting unit 43. The adjusting rod 42 has a first guidance 421 and a second guidance 422. The first guidance 421 is embodied as a guide groove extending arcuately along a periphery of the adjusting rod 42. The second guidance 422 is embodied as a guide channel extending longitudinally along the periphery of the adjusting rod 42 for a predetermined length. The adjusting unit 43 is mounted inside the support frames 12 of the carrier base 11, including a rotatable member 44 (embodied as a wheel) and a primary locating member 45. The wheel 44 is rotatable in one direction by an external force, having two retaining portions 441 and 442 formed respectively on two sides of the wheel 44 for engaging against an inner side of each support frame 12 and further stopping the wheel 44 from axial movement, a locating portion 443 formed on the wheel 44 and having a plurality of locating recesses 444 annularly arranged for detachably engaging by the primary locating member 45 and further stopping the wheel 44 from rotation, an axial hole 46 for inserting through by the adjusting rod 42, and a guide lug 47 formed in the axial hole 46 and having a distal end slidably engaging the guide groove 421 for synchronic rotation with the wheel 44 along the guide groove 421. Two retaining pieces 48 are inserted respectively through the slots of the handgrip 22 and respectively slidably engages the guide channel 422 of the adjusting rod 42 for limiting the adjusting rod 42 to axial reciprocating movement other than rotation within the predetermined length of the guide channel 422.

Referring to FIGS. 5 and 6, while operating the dumbbell 10 for increasing the weight of the dumbbell 10, the user can pull the primary locating member 45 upwards to enable the primary locating member 45 to disengage from the locating portion 443 of the wheel 44; then, the user can successfully turn the wheel 44 to enable the guide lug 47 to slide along the guide groove 421 of the adjusting rod 42 and to further enable the adjusting rod 42 to gradually axially move into the through holes 32 of a predetermined number of the weights; finally, the user pushes the primary locating member 45 downwards to enable the primary locating member 45 to engage the locating portion 443 of the wheel 44 again. When operating the dumbbell 10 for decreasing the weight of the dumbbell 10, the user can pull the primary locating member 45 upwards to enable the primary locating member 45 to disengage from the locating portion of the wheel 44; then, the user can reversely turn the wheel 44 to enable the guide lug 47 to slide along the guide groove 421 of the adjusting rod 42 and to further enable the adjusting rod 42 to gradually axially move towards the handgrip 22; finally, the user pushes the primary locating member 45 downwards to enable the primary locating member 45 to engage the locating portion 443 of the wheel 44 again. Therefore, the user can select the number of the weights as desired to adjustably change the weight of the dumbbell 10.

Further, two auxiliary locating members 51 are mounted respectively on inner sides of the two support frames 12 and 14 and located adjacent to the locating portion 443 of the wheel 44. Each of the auxiliary locating members 51 is comprised of a body, a ball 52 located in the body for engaging the locating portion 443 of the wheel 44, and a springy member 54 located in the body and biasing against the ball 52. When wheel 44 is turned for a predetermined angle, the auxiliary locating member 51 can help the primary locating member 45 to greatly secure the wheel 44 in position. In addition, the pitch between each two locating recesses 444 is designed properly such that when the wheel 44 is turned for one pitch, the adjusting rod 42 can axially reciprocate for a distance, which is equal to the thickness of one weight 31. In other words, when the user intends to increase/decrease one weight 31 on/from the dumbbell 10, the user can turn the wheel 44 for one pitch to do so. Therefore, the present invention is structurally simple, convenient in operation, and greatly accurate in adjusting the weights.

FIG. 7 shows a second preferred embodiment of the present invention, which is similar to the aforementioned embodiment but different by the following recitation. The guide lug 47 of the wheel 44 and the retaining piece 48 are designed to have spherical appearance, such that when the guide lug 47 move along the guide groove 421 or when the retaining piece 48 moves along the guide channel 422, the adjusting rod 42 can be greatly smooth in the axial reciprocating movement. 

1. A weight-adjustable dumbbell comprising: a carrier base having two support frames and a handgrip mounted between said two support frames for holding by the user's hand; a plurality of weights mounted respectively outside said two support frames and interconnected with one another, each of said weights having a through hole; and two selection devices mounted respectively at bilateral sides of said carrier base and having an adjusting rod and an adjusting unit, said adjusting rod having a first guidance and a second guidance, said adjusting unit having a rotatable member for rotation by a force, and a retaining member engaging against said carrier base for stopping said rotatable member from axial movement, a guide lug slidably engaging said first guidance of said adjusting rod, a retaining piece engaging said second guidance of said adjusting rod for stopping said adjusting rod from rotation, whereby when said rotatable member of said adjusting unit is rotated, said guide lug moves along said first guidance to drive said adjusting rod to axially reciprocate through said through holes of said weights so as to optionally select the number of said weights.
 2. The dumbbell as defined in claim 1, wherein each of said weights comprises at least one hook-like coupling portion, by which said weights can be interconnected one by one.
 3. The dumbbell as defined in claim 1, wherein said first guidance of said adjusting rod is a guide groove arcuately extending along a periphery of said adjusting rod; said guide lug of said rotatable member of said adjusting unit comprises a distal end slidably engaging said guide groove.
 4. The dumbbell as defined in claim 1, wherein said second guidance is a guide channel extending longitudinally along a periphery of said adjusting rod for a predetermined length; said retaining piece slidably engages said guide channel for stopping said adjusting rod from rotation to enable said adjusting rod to axially reciprocate within the predetermined length of the guide channel.
 5. The dumbbell as defined in claim 1, wherein said rotatable member is mounted inside said two support frames of said carrier base; said retaining members are mounted at two sides of said rotatable member for engaging inner sides of said two support frames of said carrier base.
 6. The dumbbell as defined in claim 1, wherein said rotatable member comprises a locating portion and a plurality of locating recesses annularly arranged on a peripheral edge of said locating portion; said dumbbell further comprises a locating member located beside said locating portion of said rotatable member for detachably engaging one of said locating recesses.
 7. The dumbbell as defined in claim 6 further comprising an auxiliary locating member, said auxiliary locating member being located beside said locating portion of said rotatable member and having a ball and a springy member, said ball being biased by said springy member for engaging one of said locating recesses of said rotatable member.
 8. The dumbbell as defined in claim 1, wherein said guide lug of said rotatable member is spherical.
 9. The dumbbell as defined in claim 1, wherein said retaining piece of said adjusting unit is spherical.
 10. A weight-adjustable dumbbell comprising: a carrier base having two support frames and a handgrip mounted between said two support frames for holding by the user's hand; a plurality of weights mounted respectively outside said two support frames and interconnected with one another, each of said weights having a through hole; and two selection devices mounted respectively at bilateral sides of said carrier base and having a adjusting rod and an adjusting unit, said adjusting rod having a guide groove and a guide channel, said guide groove arcuately extending along a periphery of said adjusting rod, said guide channel extending longitudinally along the periphery of said adjusting rod for a predetermined length, said adjusting unit having a rotatable member for rotation by a force, a retaining member engaging against inner sides of said support frames of said two said carrier base for stopping said rotatable member from axial movement, a guide lug slidably engaging said guide groove of said adjusting rod, and a retaining piece engaging said guide channel of said adjusting rod for stopping said adjusting rod from rotation, whereby when said rotatable member of said adjusting unit is rotated, said guide lug moves along said guide groove to drive said adjusting rod to axially reciprocate through said through holes of said weights within the predetermined length of said guide channel so as to optionally select the number of said weights.
 11. The dumbbell as defined in claim 10, wherein each of said weights comprises at least one hook-like coupling portion, by which said weights can be interconnected one by one.
 12. The dumbbell as defined in claim 10, wherein said rotatable member comprises a locating portion and a plurality of locating recesses annularly arranged on a peripheral edge of said locating portion; said dumbbell further comprises a locating member located beside said locating portion of said rotatable member for detachably engaging one of said locating recesses.
 13. The dumbbell as defined in claim 10 further comprising an auxiliary locating member, said auxiliary locating member being located beside said locating portion of said rotatable member and having a ball and a springy member, said ball being biased by said springy member for engaging one of said locating recesses of said rotatable member.
 14. The dumbbell as defined in claim 10, wherein said guide lug of said rotatable member is spherical.
 15. The dumbbell as defined in claim 10, wherein said retaining piece of said adjusting unit is spherical. 